ADL5321-EVALZ(Rev0) Ver la hoja de datos (PDF) - Analog Devices
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ADL5321-EVALZ Datasheet PDF : 16 Pages
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MATCHING PROCEDURE
The ADL5321 is designed to achieve excellent gain and IP3
performance. To achieve this, both input and output matching
networks must present specific impedance to the device. The
matching components listed in Table 5 were chosen to provide
−14 dB input return loss while maximizing OIP3. The load-pull
plots (see Figure 22, Figure 23, and Figure 24) show the load
impedance points on the Smith chart where optimum OIP3,
gain, and output power can be achieved. These load impedance
values (that is, the impedance that the device sees when looking
into the output matching network) are listed in Table 7 and Table 8
for maximum gain and maximum OIP3, respectively. The contours
show how each parameter degrades as it is moved away from
the optimum point.
From the data shown in Table 7 and Table 8, it becomes clear that
maximum gain and maximum OIP3 do not occur at the same
impedance. This can also be seen on the load-pull contours in
Figure 22 through Figure 24. Therefore, output matching generally
involves compromising between gain and OIP3. In addition, the
load-pull plots demonstrate that the quality of the output
impedance match must be compromised to optimize gain and/
or OIP3. In most applications where line lengths are short and
where the next device in the signal chain presents a low input
return loss, compromising on the output match is acceptable.
To adjust the output match for operation at a different frequency or
if a different trade-off between OIP3, gain, and output impedance
is desired, the following procedure is recommended.
For example, to optimize the ADL5321 for optimum OIP3 and
gain at 2300 MHz, use the following steps:
1. Install the recommended tuning components for a 2500 MHz
to 2700 MHz tuning band, but do not install C3 and C7.
2. Connect the evaluation board to a vector network analyzer
so that input and output return loss can be viewed simulta-
neously.
3. Starting with the recommended values and positions for
C3 and C7, adjust the positions of these capacitors along
the transmission line until the return loss and gain are
acceptable. Push-down capacitors that are mounted on
small sticks can be used in this case as an alternative to
soldering. If moving the component positions does not
yield satisfactory results, then the values of C3 and C7
should be increased or decreased (most likely increased
in this case because the user is tuning for a lower frequency).
Repeat the process.
4. Once the desired gain and return loss are realized, OIP3
should be measured. It may be necessary to go back and
forth between return loss/gain and OIP3 measurements
(probably compromising most on output return loss) until
an acceptable compromise is achieved.
FIXED LOAD PULL
FREQ = 2.6000 GHz
IP3 MAX = 41.70dBm
AT 0.4705< 86.63
10 CONTOURS, 1.00dBm STEP
(32.00 TO 41.00dBm)
POUT MAX = 14.16dBm
AT 0.6100< 136.24
10 CONTOURS, 1.00dBm STEP
(5.00 TO 14.00dBm)
GT MAX = 15.02dBm
AT 0.6100< 136.24
10 CONTOURS, 1.00dBm STEP
(6.00 TO 15.00dB)
SPECS: OFF
ADL5321
LOAD
0.404< 93.05
Figure 22. Load-Pull Contours, 2600 MHz
FIXED LOAD PULL
FREQ = 3.5000 GHz
IP3 MAX = 41.37dBm
AT 0.6911< 142.11
10 CONTOURS, 1.00dBm STEP
(32.00 TO 41.00dBm)
POUT MAX = 14.96dBm
AT 0.7686< 162.58
10 CONTOURS, 1.00dBm STEP
(5.00 TO 14.00dBm)
GT MAX = 14.02dBm
AT 0.7686< 162.58
10 CONTOURS, 1.00dBm STEP
(5.00 TO 14.00dB)
SPECS: OFF
LOAD
0.875< –147.48
Figure 23. Load-Pull Contours, 3500 MHz
FIXED LOAD PULL
FREQ = 3.6000 GHz
IP3 MAX = 41.29dBm
AT 0.7070< 140.65
10 CONTOURS, 1.00dBm STEP
(32.00 TO 41.00dBm)
POUT MAX = 15.63dBm
AT 0.7057< 161.81
10 CONTOURS, 1.00dBm STEP
(6.00 TO 15.00dBm)
GT MAX = 13.44dBm
AT 0.7057< 161.81
10 CONTOURS, 1.00dBm STEP
(4.00 TO 13.00dB)
SPECS: OFF
LOAD
Figure 24. Load-Pull Contours, 3600 MHz
Rev. 0 | Page 11 of 16
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